Used a prie-dieu (5)
I believe the answer is:
knelt
'used a prie-dieu' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for knelt that I've seen before include "Bent the knee" , "Genuflected" , "congregation did it" , "... for which one might have done this" , "Fell to one's knees" .)